Citigroup - Citi said it experienced interruptions Thursday in the availability of some of its websites. The bank noted that there were no breaches of client data.

Facebook - Facebook's Instagram unit may have lost nearly a quarter of its users after a recent flap over its change in terms of service, according to the New York Post, quoting figures from AppData. Instagram had 16.4 million active daily users the week it rolled out its policy change, but that number has now fallen to 12.4 million, the paper reported.

Omeros Corp. - The drug developer's treatment for arthroscopic knee surgery patients did not show the same post-operative benefits in a phase 3 clinical trial that had been seen in an earlier study.

Apple - Apple has been fined 1 million yuan ($160,400) by a Chinese court for hosting third-party apps in its App Store that were selling pirated electronic books. A group of Chinese authors who brought a suit against Apple, however, were disappointed with the verdict, having sought 10 times that amount.

MagicJack VocalTec - The telephone service provider has raised its estimates for the fourth quarter and the full year, because of lower expenses as well as higher sales. Separately, magicJack has named chairman Gerald Vento as chief executive officer, effective Jan. 1. Board member Donald Burns will succeed Vento as chairman.